Method of manufacturing balloons



Feb. 8, 1949. E. E. HABlB El AL 2,461,271

METHOD'OF MANUFACTURING BALLOONS Original Filed Feb. 19,1946

INVENTOR. Emi/ef. Habib David 6. Green/fa A fforney Patented Feb. 8, 1949 UNITED STAT S FATE-NT ()F FIGE I METHOD OF MANUFACTURING BALLOONS ease in. Habib, Belmont, at have (1. creates, Wayland, Mass assignors to Deweyand Anny Chemical company, North Cambridge, Mass, a" corporation of Massachusetts 6, 1947, Serial No. 766,742; a

In Canada January 25, 194

2 Claims.

This invention relates to manufacture of 1 n u' w inflatable objects and is particularly adapted to the manufacture of meteorological balloons of medium and large size; These balloons must fit standardized inflationequipment. It is essential, therefore, that the balloons have standardized neck diameters split the inflating apparatus which exists'in the field.

Recently, there has been a need for meteorological balloons having inflated diameters at 760 mm., of approximately 8 feet and even larger. If balloons of such size are manufactured by gel inflation techniques, e. g., by that process disclosed, .in the patent to Habib and Gott No.

2,373,702, dated June 19, i945, and if the neck diameter of the larger moldrequired to make" weakly attached to the balloon envelope and tear outof the envelope when any heavy wind strain is imposed. o The present invention permits the manufacture of meteorological balloons having necks which are so securely attached to the balloon en- ,0

velo e that they will withstand any strain that the" balloon envelope proper will take. In addition, the invention makes it possible to make a balloon having a substantial body diameter yet possess a much smaller diameterneck than any which has heretofore been. possible.

We have discovered that if a mold is" provided which will form an intermediate section of gel betweenthe body and the neck which possesses a considerably greater diameter than the neck itself, that when the gel is inflated, the intermediate portion will" be drawn into the lower hemisphere of the balloon envelope, But this new portion of the hemisphere will taper frorn the full thickness of the neck Where it joins the neck to its juncture with the envelope where it has only. the thickness of the envelope.

Additionally, the diameter of this tapered zone isldirectly related to the original diameter and length of; the intermediate section and to the gel form, butother methods. of gel expansion such as liquid pressure, stretching by pulling, or exhausting the air in the surrounding space are not excluded. e I l V The invention may be more readily understood by reference to the drawings, in which Figure l is an elevation of the preferred form of the dipping mold; y t

Figure 2 is a transverse section taken on the 1ine 2-2 of Figure 1; I v v V Figu,re 3 is a sectional elevation of a portion of an inflated balloorrenvelope; and

Figure} is an elevation of a modified form of balloon mold,

Referring to Figure l the mold H1 preferably formed with a. shank portion H; and a body or flute portion l2 Intermediate the'flute portion i2 and the shank l l the flutes lose their lunette form and extend parallel to the axis of the shank When following any accepted; gel inflation technique, themold I0 is dipped into'an aqueous dispersion of rubber up to a line on the shank I I which is indicated by the reference numeral l l. When a deposit of sufllcient' thick'nifzs has been formed, the mold is withdrawn and the rubber deposit, stillin a plastic, gel stage, is stripped fromthe mold." The endof the neck portion 6 of the deposit is fitted over aninflation nozzle N, then a clamp or tape-tie istied about the hook at the point lb. The gel is then inflated.

We have found that if the balloon is to bear)- proximately spherical, the axial perimeter of the flutes including the portions l2 and J3 must e'oual approximately the transverse maximum perimeter, i. e., the perimeter of the section 2-3. When other shapes are required, this ratio-of perimeters is no longer necessary As Figure 3 showsg the neckt of the gel remams the same diameter as the inflating nozzle'but that portionl'b of the deposit which was formed en the parallel section" l3 of the flutes, flaresout into the body of the balloon with-a generally tapering' v cross section which is thinnestwhere the portion ijfi joins the body of the envelope, as

indicated at 1'7, and thickest where the portion 7 (b) By the perimeter of the same section, and

By the amount of the gel extension introduced by the gel-inflation step.

In order for the reinforcing section to taper smoothly from the balloon body to the neck, it is preferred to hold the ratio of the perimeter of the gel formed on the mold section 13 to the maximum perimeter of the gel formed on the flutes [2 to approximately 6:1 or less. If the diiference in perimeters is much greater than 6:1, then for any given inflation pressure, the lunette sections I2 will expand practically to the exclusion of the reinforcing section i3. In this case, a thinning and weakening of the gel at the point i7 sometimes occurs. When the perimeters ratios are held approximately to the recommended limits, the intermediate section I3 is drawn smoothly into the body of the balloon.

Figure 4 illustrates the shape of mold found useful when the balloon envelope must be large and the neck quite small. The first step 1'9 of the reinforcing zone has a perimeter which is one-sixth or a larger fraction of the maximum perimeter of the body portion of the gel. The second step 20 has a perimeter which in turn is one-sixth or a larger fraction of the perimeter of the gel formed on step (9. Obviously, as many steps as are necessary may be used to produce a smooth, tapered reinforcing flange between the body of the balloon and the neck. Two steps, however, will produce a finished balloon having an envelope diameter of 12 feet and a neck diameter of 2 inches.

The word perimeter" as applied to fluted molds means the unfolded or developed distance progressively from root to apex of the convolutions around the form of the gel deposited upon the forming flutes as the sense requires.

The word rubber, has been used to include natural rubber having the proper characteristics, for example, see Patent No. 2,378,700, chloro-butadiene-l,3 and the various artificial elastomers the gels of which possess suiilcient strength to permit the requisite expansion.

For convenience in the specification and claims we have used the word gel, to denote low body and with molds of any construction.

For example, spherical molds may be built according to this invention with a cylindrical intermediate flange-forming section interposed between the sphericalbody and the shank of the mold. Although the process is primarily adapted to the manufacture of hollow articles by the socalled coagulant dip process, it is useful in connection with cast as well as dipped rubber products.

Balloons produced by this invention have successfully met the requirements for small necks, large envelopes, and possess suiiicient strength in the neck reinforcement to suspend meteorological apparatus in all normal weather conditions.

This application is a division of application Serial No. 548,674, filed February 19, 1948.

We claim:

1. The method for forming balloons and similar hollow objects having a neck reinforcing zone on the body of the balloon which consists in providing a hollow expansible gel having a stepped portion intermediate the body portion and the neck portion, that part of the intermediate portion adjacent the neck having a diameter greater than but not exceeding approximately 6 times the diameter of said neck and that part of the intermediate portion adjacent the body having a diameter less than but not less than one-sixth of the body portion of said gel, securing the neck portion of the gel against expansion throughout substantially the entire length thereof, expanding the gel by fluid pressure, and drawing the stepped portion of the gel beyond the neck portion into the body of said balloon by said expansion while retaining the molded neck diameter.

2. The method of forming balloons and similar hollow objects having a reinforcing zone on the body of the balloon which consists in providing a hollow expansible gel having a body portion, a neck portion and an intermediate portion between said body portion and said neck portion which is of greater diameter than said neck but not exceeding approximately 6 times the diameter of the neck portion and of lesser diameter than but not less than one-sixth of the diameter of said body portion, securing the neck portion of the gel against expansion throughout substantially the entire length thereof, expanding the gel in the body portion by fluid pressure and drawing the intermediate portion beyond the neck portion into the body of said balloon by said expansion to form a tapered reinforcing flange on the body of the balloon surrounding said neck while retaining the molded neck diameter.

EMILE E. HABIB. DAVID G. GREENLIE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,236,306 Bratring Mar. 25, 1941 2,378,701 Habib et al June 19, 1945 2,378,702 Habib et al June 19, 1945 Certificate of Correction Patent No. 2,461,271. February 8, 1949;

EMILE E. HABIB ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 3, line 44, for the Words form of read form or; column 4, line 13, for the year 1948 read 1946;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 27th day of September, A. D. 1949.

THOMAS F. MURPHY,

, Assistant Uommzssioner of Patents. 

